1. Field of the Invention
The present invention relates to a plasma display device. More particularly, the present invention relates to a plasma display device having a simplified chassis base structure and a grounding module for enhancing grounding of a printed circuit board assembly.
2. Description of the Related Art
A plasma display device is an apparatus that displays an image from a plasma display panel (PDP) using plasma generated by a gas discharge. Typically, the plasma display device includes the PDP, a chassis base supporting the PDP, and a plurality of printed circuit board assemblies (PBAs) mounted to the chassis base on a side opposite of the PDP. The PBAs may be connected to display electrodes or address electrodes via, e.g., flexible printed circuits (FPCs) and connectors.
A typical PDP includes two glass substrates attached to each other at peripheral regions of their surfaces with a discharge space formed therebetween. Generally, the PDP exhibits weak mechanical strength and is susceptible to damage from physical impact. PDPs also produce substantial amounts of heat during operation and can suffer from excessive heat buildup. To address this heat buildup problem, a thermal conduction sheet may be provided along the rear side of the PDP to conduct and channel the heat produced by the PDP away from the PDP by spreading and dissipating the heat in planar directions.
The chassis base is generally formed of a metallic material having sufficient mechanical strength to support the PDP, and the PDP is attached to one side of the chassis base using, e.g., a double-sided adhesive tape disposed along the peripheral edges of the PDP. The chassis base performs several functions, including providing physical reinforcement to the PDP, supporting the PBAs, dissipating heat generated by the PDP, preventing electromagnetic interference (EMI), providing a ground structure, etc. The chassis base may be provided with separate reinforcement for enhancing its strength. In order to mount the PBAs, the chassis base may be provided with a plurality of bosses. The bosses are grounded such that EMI produced by the PBAs may be reduced. The PBAs may be mounted and fastened onto the bosses provided on the chassis base using, e.g., fasteners.
Typically, the PBAs are provided with a circular grounding area, e.g., a hole, at the fastening portion of the PBA. The PBAs are grounded through this grounding section such that the EMI may be reduced. The grounding section is typically a circular penetration hole of the PBAs. As the PBAs may include a plurality of layers, e.g., insulating and conducting layers, the grounding section may pass through a number of layers. Further, the grounding section may be in contact with one or more layers.
The PBAs are placed on the bosses such that the grounding sections of the PBAs are placed on bosses after which fasteners are used to fasten the PBAs to the bosses using the circular penetration holes in the PBAs and fastening holes, e.g., threaded holes, in the bosses.
In order to ensure that the PBAs remain in place on the bosses, and in order to ensure satisfactory electrical connections between the grounding section of the PBAs and the bosses, the fasteners, e.g., fasteners, may need to be installed under significant tension. That is, the fasteners may need to be torqued to a predetermined value in order to ensure application of sufficient compressive force to maintain the physical and electrical connection between the PBAs and the bosses. However, the fastening force from the fasteners may cause distortion of the grounding sections of the PBAs, particularly those having a multi-layer structure.
In particular, the construction and materials of the PBAs is not optimal with respect to the amount of compressive force that can be applied thereto. As a result, torquing the fasteners to the predetermined torque may cause an inelastic deformation of the PBAs in the grounding section, permanently distorting them. Such distortion of the grounding section may cause a thermal distortion of the PBA as a result of the heat produced during an operation of the PDP, thereby causing fasteners to become unfastened from the fastening hole over time. Further, the inelastic deformation of the PBAs may result in insufficient tension on the fasteners, thereby causing the fasteners to become unfastened. As a result, the grounding of the PBA may deteriorate, and, accordingly, the EMI may be increased.
The information provided above sets forth an overview of the problems that the present invention is designed to overcome. However, the information does not constitute prior art.